# Nutrition in chronic kidney disease (stage 4-5)
When the kidneys are severely damaged, the way your body handles nutrients changes. Nutrition therefore plays an important role in how you feel and function. Below is what research on this topic has shown.
Protein intake and muscle mass
In severe kidney disease (stage 4-5), kidneys are less able to remove waste products from protein breakdown. This limits how much protein is suitable, but at the same time muscle loss is a risk if intake is too low.
ResearchediPositive results in clinical studies, not yet standard treatment
Recent research shows that the balance between protein amount, diet quality and physical activity influences muscle strength and nutritional status in dialysis patients. Malnutrition and muscle loss can have serious consequences, including for recovery ability.
The right amount of protein per day must be determined individually and depends on whether you are already on dialysis, what type, and other factors. For this you need to consult your doctor or dietitian.
Potassium and fluid balance
Healthy kidneys regulate potassium. At stage 4-5, potassium can build up in the blood, which can cause heart and muscle rhythm disorders.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Too much potassium is harmful; many foods contain potassium. Dialysis removes potassium; without dialysis, intake usually needs to be limited.
Foods high in potassium (such as certain vegetables, fruits, nuts and certain dairy products) may need to be restricted, but this is highly individual and depends on your remaining kidney function, dialysis schedule and laboratory values. Your doctor or dietitian will determine what is appropriate.
Fluid intake also plays a role: with dialysis, fluid must be significantly restricted between sessions to avoid overload.
Phosphorus and calcium balance
Kidneys also regulate phosphorus. At stage 4-5, phosphorus can build up, which can promote bone demineralization and vascular calcification.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Elevated phosphorus levels are associated with worse health outcomes. Many foods (especially dairy products, meat, certain grains) contain high amounts of phosphorus.
Some patients use phosphate binders to reduce absorption; this is a medication matter you discuss with your doctor. For food choices, a dietitian can help determine which foods are appropriate.
Micronutrients: zinc and other substances
Dialysis and the disease process itself can lead to loss or deficiency of certain minerals and vitamins, including zinc.
ResearchediPositive results in clinical studies, not yet standard treatment
Recent studies suggest a link between zinc deficiency and progression of heart and kidney complications. Dialysis patients are at risk of zinc deficiency.
Zinc is found in foods such as meat, fish, eggs and certain seeds. Whether supplementation is needed should be determined through blood tests and discussed with your healthcare provider. Self-supplementation can cause interactions with medications.
Similarly, vitamin D, iron and B vitamins (especially B12 and folic acid) can become imbalanced. This requires individual monitoring.
Salt and blood pressure regulation
Too much salt can raise blood pressure and worsen fluid retention.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Reducing salt intake helps with blood pressure control in kidney disease.
Most food preparations, industrial products and restaurant meals contain a lot of salt. Cooking at home with less salt is an important measure here.
Eating patterns and inflammatory processes
Research looks at the effect of certain eating patterns (for example Mediterranean diet, plant-based oriented choices) on inflammatory markers and disease progression.
ResearchediPositive results in clinical studies, not yet standard treatment
Some dietary patterns appear to be beneficial for reducing inflammation and kidney disease progression, but research is not yet conclusive. Individual tolerance varies widely.
This is not a reason to suddenly change your eating pattern without guidance. Discuss this with your dietitian, who will take your specific restrictions (phosphorus, potassium, protein, fluid) into account.
Interactions between nutrition and medication
Certain foods can interact with medicines you take for stage 4-5 kidney disease.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Food can affect the absorption and effectiveness of, for example, ACE inhibitors, potassium-sparing diuretics, and phosphate binders. Grapefruit juice can also affect certain medicines.
Always inform your doctor or pharmacist whether food could affect your medicines.
Fluid restriction
For dialysis patients (stage 5 on dialysis), fluid restriction between sessions is essential.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Too much fluid retention between dialysis sessions leads to overload of the heart and lungs and risk of complications.
Fluids don't just count as drinks: soups, ice cream, fluid from food and fluid provided by medicines also count. You should agree the allowed amount with your treatment team and dietitian.
Nutritional guidance by specialists
Nutrition is so multifaceted in stage 4-5 that professional guidance is highly recommended.
ProveniIncluded in official guidelines, or approved by EMA or FDA
Patients guided by a dietitian have better values and better wellbeing than those without guidance.
A nephrology dietitian (specialist in this field) can draw up a nutrition plan that takes into account your laboratory values, symptoms, preferences and treatment. This plan can be adjusted several times a year as your situation changes.
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_This information never replaces a doctor's judgment. Always discuss your situation with your own healthcare provider._